Merge Existing Error Articles

Merge an approved list of standalone compiler error or warning articles into an existing consolidated destination. Process the entire approved list, then stop; searching and thematic consolidation are separate skills.

Required Inputs

Collect these inputs from the user:

• Destination filename: The consolidated .md file in docs/csharp/language-reference/compiler-messages/.
• Theme description: The theme shared by the diagnostics.
• Source files: The user-approved list of existing articles to merge.

Key Paths

• Destination: docs/csharp/language-reference/compiler-messages/{destination-filename}
• TOC: docs/csharp/language-reference/toc.yml
• Redirections: .openpublishing.redirection.csharp.json
• Redirect skill: .github/skills/redirect-article/SKILL.md
• Redirect script: .github/skills/redirect-article/scripts/create-redirect-entry.ps1

Batch Process

For each source file in the approved list, complete all the following steps.

1. Read and Extract

Read the source and extract:

• The error code from the filename or front matter, such as CS0220.
• The verbatim compiler message:
  1. Extract the code's numeric portion.
  2. Find the constant assigned that number in ../roslyn/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs.
  3. Find the matching <data> element in ../roslyn/src/Compilers/CSharp/Portable/CSharpResources.resx.
  4. Read its <value> child.
• The article body after its front matter and H1.

2. Update the Destination

In the front matter, add the code to f1_keywords and helpviewer_keywords in numeric order.

Add the code to the master error list in numeric order:

- [**CS{NNNN}**](#anchor-tbd): *{verbatim compiler error message}*

Use #anchor-tbd until the consolidation phase assigns thematic anchors.

Replace Roslyn format placeholders such as '{0}' and '{1}' with descriptive terms while preserving the static message text and producing a coherent sentence. Prefer context-appropriate generic terms such as 'type', 'value', 'operator', 'member', or 'method'. For example, Constant value '{0}' cannot be converted to a '{1}' becomes Constant value 'value' cannot be converted to a 'type'. Use the following XML <comment> element, when present, to identify placeholder meanings.

Append the source content as a new H2 section:

## CS{NNNN}

{source article content, adapted to fit as a section rather than a standalone article}

Remove the source front matter, H1, and See also section. Demote existing source headings one level so source H2 headings become H3 headings, and so on.

3. Create the Redirect

Follow the redirect-article skill. Use its script; do not manually edit the redirection JSON:

./.github/skills/redirect-article/scripts/create-redirect-entry.ps1 `
    -RedirectionFile ".openpublishing.redirection.csharp.json" `
    -SourcePath "docs/csharp/language-reference/compiler-messages/{source-filename}" `
    -RedirectUrl "/dotnet/csharp/language-reference/compiler-messages/{destination-filename-without-extension}"

If the source is under docs/csharp/misc/, use that location in SourcePath. Also follow the redirect skill's requirement to find and update repository links to the deleted article.

4. Update the TOC

In docs/csharp/language-reference/toc.yml:

• Add the code to the destination entry's displayName, maintaining numeric order.
• Find and remove the source file's complete TOC entry, including its - name: and href: block.

5. Delete the Source

Delete the source Markdown file after its content, redirect, links, and TOC entry have been handled.

Present the Batch Summary

After processing every approved source, present:

• All source files merged.
• The count of error codes added.
• All redirects created.
• All TOC entries removed.

Do not proceed to searching or thematic consolidation.